Check engine light turned off by itself... what to do?
 

Happy to provide more detail but I’ll try to keep it short:I have a 2006 with 190k miles, bought in 2010 with 62k miles.

- Almost two weeks ago my #1 cylinder fuel valve got stuck open, flooding the chamber, throwing codes, lighting up the dash, and causing the vehicle to misfire and shake.

- After a round of cleaning (described as like an IV drip for the engine), the issue was solved and I put another thousand miles on it.

- then yesterday morning, the lights came on again (check engine, VSC off, VSC trac, and traction control). I took it to the shop and was told that I would need a new exhaust manifold (to include cat. converter). While it could be due to age/mileage, it was likely exasperated by the first issue.

- after 2 days and maybe 40 miles (light driving due to issue, until the parts arrive), the lights are off. Despite being on for the past two days every time I drove the car (multiple short trips of less than 10 miles), they just turned off.

So... does the work still need to be done?

I was quoted under $800 for parts and labor. Normally, I would assume the work still needs to be done. However, if a bolt breaks, it will cost an hour of labor to to drill it out. If all 8 bolts break I’m looking at a total of $2K!
Not really something I want to spend unless absolutely necessary.

Hoping to keep this car for a while (until it costs me too much) but planning to replace it soon as my daily driver/commuter.

I have browsed the forum for years and am always surprised by the depth of knowledge on this board. Thanks.

Problem doesn't exist anymore probably cleared after a couple of cycles. Not saying it won't come back.

I'd personally hold off and see if it comes back.

That’s exactly what I want to hear, but figured I’d ask to make sure I wasn’t doing more damage if I kept driving.

Did you happen to fuel up before the lights went off? Sometimes just a loose gas cap with throw codes.

In this case, I don’t think that was the problem. It threw the same code (concerning catalytic converter, and I got the same code when I took it to auto zone to read the code).

The frustrating part now is that the lights keep turning off for a few days, then back on. I have an apt scheduled for tomorrow to replace the exhaust manifold (the cat. converter is connected to this one piece). My only hesitation is that if all 8bolts break the job will go from $7-800 to $2k due to the estimated time to drill out the broken bolts!

Here is the timeline:
-June 12 am- check engine, VSC Off, VSC Trac, and traction control lights all turned on. Diagnosed that afternoon and told it was cat converter.
-June 13 pm- lights went off, got gas on the 13th, but after the lights already went back off.
-June 15 noon- lights back on.
-June 18 pm- lights back off, got gas on the 19th.

Hoping someone has suggestions because I this seems like a (financially) risky procedure. I’ve also found out about using a sensor extender (Say Hello to my Lil Friend) but don’t really understand how this works or fixes the problem. I was told that if the cat converter gets stopped up then the exhaust won’t work, and eventually the car won’t start.

Hoping someone else has experienced this. I’m wondering if the cat converter is just on the line of going bad so it is toggling the lights/computer codes on and off, and this the procedure sounds like it needs to be done.

But with $2k on the line, I need to be sure

Otherwise, it’s been pretty trouble free. 1) Had to replace exhaust pipe tens of thousands of miles ago (maybe around 120k?) because it rusted off of the Muffler. 2) replaced both front axels about 20-30k mules ago due to cv boots. 3) replaced shocks and struts about 10k miles ago. 4)almost forgot about the new radiator about 30k miles ago due to a leak. Sounds like a lot as I write it up, but this has been maybe one major thing a year, maybe longer. Hoping to keep this running until at least 220k minimum.

Thoughts?

I'm very curious to why they are saying its the whole converter.

What codes are you getting?

Can I recommend investing in a cheap code reader? Even though the CEL is now off, you may still have codes 'pending'. Most faults need to be detected multiple times (usually twice) before the CEL is activated. Additionally, for a fault to be detected, the engine has to have completed a certain 'cycle' or met certain conditions first.
It's possible that your fault still exists, but not enough to trigger the CEL. With a code reader you can view fault codes that are pending. This will help you truly know if the problem has been corrected, or is still lurking.

Can’t recall the exact code, but auto zone read it as well and came up with the same answer.

UPDATE:
Got it back from the shop with a new exhaust manifold/ cat converter. None of the bolts broke, so that’s a plus. Unfortunately, now they are saying I need a new air/fuel sensor, so off to research that. It’s a $500 part though!

Damn these costs are starting to add up. They said it’s so expensive because it’s basically OEM, made by some Japanese company (name starts with a D, but can’t remember).



A code reader isn’t a bad idea, I’ll have to look into one.

In case anyone is following this thread, I found some good info here: Air Fuel Ratio Sensor and o2 Sensor Replacement - P0136 and P2195

As it reads to me, the AFS is forward of the cat converter and the O2 sensor is aft/behind the cat converter. The car should have two of each, one in front and one behind each of the two cat converters which are attached to the exhaust manifold.

Denso?

So its $50 bucks for the part and $450 for the lube they using to stick it to you?

That lube seems pretty pricey. I wonder if they will let me supply my own.
Haha!

But yeah, that company sounds familiar.